Process of neutralization for hydrocarbon oils



Jan. 2, 1934. L, CALDWELL ET AL PROCESS OF NEUTRALIZATION FOR HYDROCARBON OILS Filed Dec. 8, 1930 fay/77017 7777 L I, A TY'ORNE) Patented Jan. 2, 1934 UNITED STATES PATE 'FFEE PROCESS OF NEUTRALIZATION FOR HYDROCARBON OILS Application December 8, 1930. Serial No. 500,968

8 Claims.

This invention relates to a process of neutralization of acid oils and has for its principal object the prevention of formation of gummy compounds in motor fuels and other hydro-carbon oils.

In the ordinary treatment of petroleum distillates, particularly the pressure distillates derived from cracking petroleum, or its fractions, it is customary to treat such distillates with sulphuric acid or" diiferent strengths to remove un- 10 saturated and other undesired compounds. After the bulk of the acid sludge is removed, the distillate is in an acid condition, containing from 40 to 600 milligrams, or more, of acid (calculated as HzSOi) per liter. This acid is then neutralized 1 with a caustic solution and washed, after which the distillate may be redistilled and then sweetened to remove objectionable sulphur compounds. However, it has been found in such ordinary and well known steps that the redistillation of an acid treated distillate after neutralization invariably yields an acid distillate which may be due to the breaking down of certain di-alkyl esters by the heat of distillation, the same even breaking down on standing for a period at room temperatures without distillation.

sulphuric acid and the corresponding hydrocarbon radical and such acid thereupon acts upon certain unsaturated bodies always present to form gums, or gum forming compounds which are difficultly removable, or observable until after a period of time and which are highly detrimental to the working parts of an engine in which the distillate may be used.

Whether this theory of formation is correct, or not, the fact remains that the distillation of an acid treated distillate of any kind yields an acid condensate, even though presumably all the acid has been removed therefrom before distillation.

It is, therefore, an object of this invention to produce a distillate, or motor fuel,-containing a minimum quantity of detrimental gums and therefore having a stable color.

As an illustration of the process, and referring to the drawing, an acid treated pressure distillate was passed through a pipe 10 into a column 11 which was filled a pretermined depth with a neutralizing agent 12, such as lump magnesium oxide (MgO), or brucite (Mg(OH)2) together with a stream of water from a pipe 13 into which is introduced a slurry of MgO and water from a reservoir 14.

The effect of such passage of distillate is to yield a stream of neutralized distillate which passes through a pipe 15 to a separator 16, where- Such breaking down of the di-alkyl esters yields,

in a separation of the water containing water soluble reaction salts and the distillate takes place, the water being drawn off through a pipe 17 while the distillate passes through a pipe 18 to a steam still 19 having the upper portion filled with a similar neutralizing agent in lump form, such as MgO, or brucite. Still 19 is provided with an open steam pipe 20, closed steam coils 21, and a bottoms discharge pipe 22, the vapors passing through a conduit and condenser 24 to provide a distillate in receiver 25, from which it is withdrawn through pipe 26.

The steps of neutralizing the acid treated distillate up to the pipe 18 are described and claimed in the copending applications, of Lyle Caldwell, Serial No. 447,275, filed April 25, 1930, Serial No. 480,807, filed September 9, 1930, Serial No. 488,- 573, filed October 14, 1930, and in the copending application of Raymond Thayer I-Iowes, Serial No. 496,417, filed November 18, 1930, and such steps, while preferred to be used in the present process, may be replaced by steps in which neutralizing may be accomplished in other well known manners, such as by caustic soda solution, etc.

To distinguish from other known processes in which a neutralized oil passes through pipe 15 to separator 16 and is therein sweetened with a hypochlorite solution (such as 34% of 8 Baum sodium hypochlorite) introduced through pipe 27, the thus sweetened distillate is passed into steam still 19 (which then contains no neutralizing agent) and a 75% overhead is recovered in receiver 25 wherein it is resweetened with 64%. of the same hypochlorite solution. Such distillate when so treated by such known process when taken from pipe 26 yields 370 milligrams of gums per 100 c. c. by the well known standard copper dish test.

If new still 19 is filled with a neutralizing agent, 5 such as lump MgQ'or brucite (Mg(Ol-I)2), and the distillate is steam distilled in the column without sweetening in receiver 25, the distillate yields but 40 milligrams of gums per 100 c. c.

If now further, still 19 is still filled with the 100 described neutralizing agent and the recovered distillate is sweetened in receiver 25 with .5% of an 8 Baum sodium hypochlorite solution, the quantity of gums per 100 c. 0. increases to 125 milligrams.

'This indicates that the usual hypochlorite sweetening steps are quite favorable to the formation of deleterious gummy compounds which is believed to be due tostrong oxidizing effect of 1 hypochlorite solution on the distillates causing polymerization of certain of the hydrocarbons.

The formation of such gummy compounds may be practically entirely prevented by passing the neutralized distillate into still 19', which is partially filled" with the described neutralizing agent, without treatment with hypochlorite treatment in separator 16, and the condensate recovered from the distillation in still 19 in receiver 25' is sweetened with a minimum quantity of sodium plumbite (PbO) solution. Such solution may be introduced through pipe 28 and subjected to any suitable form of agitation in receiver 25 prior to withdrawal, after settlement, through pipe 29 in a well known manner.

The distillate, thus treated, is found to contain but 3.4 milligrams of gums per 100 c. c., is of stable color up to 30and is ready for use as a fuel, a thing which has never before been accomplished when running a pressure distillate by other known methods in the same steps. treating, it is preferred to maintain the distillate in alkaline condition throughout the process, as it appears this factor is largely controlling in eliminating the formation of gums.

' The neutralizing agent, MgO or Mg(OI-I) 2, used instill 19 is one which naturally lends itself to such a vapor phase treatment inasmuch as it is only reactive in the presence of moisture (which is provided by the steam from pipe 20) to form water soluble salts and such salts are removed (as fully described in said copending applications) after the treatment of a given volume of distillate by flushing the apparatus with water.

Further, the breaking down of any di-alkyl esters, as described, takes place in the presence, and about the interstices, of the neutralizing agent and in the presence of moisture so that any sulphuric, or sulphurous, acid which may be formed is immediately neutralized and cannot recombine with other hydrocarbons to form gummy compounds on condensation. Also the immediate neutralization of such acid prevents a damaging corrosion of the apparatus.

45, In this manner, unsaturated compounds re- -main unpolymerized and in a relatively stable condition whereby they have high value as antiknock compounds in the finished distillate.

The herein described process is not limited in its application to acid vapors but is useful in the neutralization of gases, vapors, or fumes of an acid character, such as natural gas, stack gases from smelters and the like, which contain S02, or other acid gases, such as hydrochloric acid 55, vapors or the like.

The brucite (Mg(OH) 2), or the magnesium oxide .(l /IgO), are substantially insoluble in water (below 1%), but have sufficient solubility to react with the acid and thus render the oil neutral 60, or slightly on the alkaline side, it being understood that when MgO is slurried with water that the water insoluble suspenoid magnesium hydroxide (Mg(OH)2) is formed.

In this manner in the present process the reactions taking place in columns 11 and 19 are always performed in the presence of an excess of alkaline solution, which, taken with the alkaline sweetening reagent (PhD) in receiver 25, apparently permits but a minimum formation of gums m or eliminates such formation entirely.

We claim as our invention:

1. A process of neutralizing which comprises:

Inso passing hydrocarbon oil which has been treated with a mineral acid, in contact with a granulated body of substantially water insoluble material containing a solution of magnesium hydroxide whereby water soluble salts are formed from the neutralizing of' said acid by said solution, vaporizing the so treated oil, passing the vapors in contact with a body of similar neutralizing material in the presence of aqueous fluid, condensing said vapors; and treating the condensate with an alkaline sweetening reagent.

2. A process of neutralizing which comprises: passing hydrocarbon oil which has been treated with a mineral acid, in contact with a granulated body of substantially water insoluble material containing a solution of magnesium hydroxide whereby water soluble salts are formed from the neutralizing of said acid by said solution, vaporizing the so treated oil, passing the vapors in contact with a body of similar neutralizing material in the presence of aqueous fluid, condensing said vapors, and treating the condensate with sodium plumbite.

3. A process of treating oil which comprises: neutralizing hydrocarbon oil which has been treated with a mineral acid, vaporizing the neutralized oil, passing the vapors in contact with a body of contact material containing a solutionof magnesium hydroxide, condensing the vapors, and treating the condensate with sodium 1 5 plumbite.

4. A process of treating oil which comprises: neutralizing hydrocarbon oil which has been treated with a mineral acid, vaporizing the neutralized oil in the presence of steam, passing no the mixed vapors in contact with a body of contact material containing a solution of magnesium hydroxide, condensing the vapors, and treating the condensate with sodium plumbite.

5. A process of treating oil which comprises: 5 neutralizing hydrocarbon oil which has been treated with a mineral acid, vaporizing the neutralized oil in the: presence of steam, passing the mixed vapors in contact with a body of material yielding magnesium hydroxide and containing a solution of such hydroxide, condensing the vapors, and treating the condensate with sodium plumbite.

6. That step in a process of treating oils which comprises: vaporizing a neutralized mineral acid treated distillate with steam and passing the mixed vapors in contact with a body of material containing a solution of magnesium hydroxide capable of reacting therewith and of producing watersoluble salts.

7. That step in a process of treating oilswhich comprises: vaporizing a neutralized mineral acid treated pressure distillate with steam and passing the mixed vapors in contact with a body of brucite then capable of reacting therewith to produce 1 water soluble salts.

8. A process of treating oils which comprises: neutralizing a mineral acid treated pressure distillate, vaporizing the neutralized distillate in the presence of steam, passing the mixed vapors in contact with a body of contact material containing MgO to react therewith and form water soluble salts, condensing the vapors, and treating the condensate with sodium plumbite.

LYLE CALDWELL; RAYMOND THAYER HOWES. 

